20Cr4 (France / AFNOR NF) Material Properties

Other designations:
Material group: Ferrous Alloys / Structural and constructional steels
Country/Standard: France / AFNOR NF

Data updates

Latest Update: 2024-12
Total number of updates: 6
Update History:
2023-12 2020-12 2018-10 2018-08 2015-05

Mechanical Properties

Temperature

0 - 30°C
PROPERTY / VALUE
Brinell Hardness (HB) 140 — 240 view details
Grain Size Fine grain steel shall have an austenite grain size of 5 or finer. Sampling and sample preparation shall be as specified in ISO 643. The grain size shall be determined from a carburized specimen. Carburization shall be achieved by maintaining the specimen in carburizing powder at 950°C ± 10°C for 6 h. This is generally done by keeping the carburizing chamber at 950°C ± 10°C for 8 h, including a preheating period. In most cases, a carburized layer of approximately 1 mm is obtained.; Grain size of 5 or finer in accordance with ISO 653.; Steel shall have an austenite grain size of 5 or finer in accordance with ISO 643. view details
Brinell Hardness (HB) 140 — 240 view details
Grain Size Fine grain steel shall have an austenite grain size of 5 or finer. Sampling and sample preparation shall be as specified in ISO 643. The grain size shall be determined from a carburized specimen. Carburization shall be achieved by maintaining the specimen in carburizing powder at 950°C ± 10°C for 6 h. This is generally done by keeping the carburizing chamber at 950°C ± 10°C for 8 h, including a preheating period. In most cases, a carburized layer of approximately 1 mm is obtained.; Grain size of 5 or finer in accordance with ISO 653.; Steel shall have an austenite grain size of 5 or finer in accordance with ISO 643. view details

Physical Properties

Temperature

0 - 30°C
PROPERTY / VALUE
Modulus of Elasticity 190 — 210 GPa view details
Density 7.67 — 7.86 kg/dm³ view details
Poisson Coefficient 0.27 — 0.3 view details
Modulus of Elasticity 27.6 E+03 — 30.5 E+03 ksi view details
Density 0.277 — 0.284 lb/in³ view details
Poisson Coefficient 0.27 — 0.3 view details

Composition

CRITERIA
VALUE
UNIT
CAS NUMBER
CRITERIA
Al
VALUE
≤ 0.050
UNIT
%
CAS NUMBER
7429-90-5
CRITERIA
C
VALUE
0.17 – 0.23
UNIT
%
CAS NUMBER
7440-44-0
CRITERIA
Ca
VALUE
Intentional additions of calcium or calcium alloys for deoxidation or inclusion shape control are not permitted unless specifically approved by the purchaser.
UNIT
%
CAS NUMBER
7440-70-2
CRITERIA
Cr
VALUE
val1
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UNIT
%
CAS NUMBER
7440-47-3
CRITERIA
Cu
VALUE
val1
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UNIT
%
CAS NUMBER
7440-50-8
CRITERIA
H
VALUE
val1
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UNIT
%
CAS NUMBER
1333-74-0
CRITERIA
Mn
VALUE
val1
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UNIT
%
CAS NUMBER
7439-96-5
CRITERIA
O
VALUE
val1
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UNIT
%
CAS NUMBER
7782-44-7; 17778-80-2
CRITERIA
P
VALUE
val1
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UNIT
%
CAS NUMBER
7723-14-0
CRITERIA
S
VALUE
val1
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UNIT
%
CAS NUMBER
7704-34-9
CRITERIA
Si
VALUE
val1
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UNIT
%
CAS NUMBER
7440-21-3
CRITERIA
Ti
VALUE
val1
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UNIT
%
CAS NUMBER
7440-32-6

EN ISO 683-17: 2023 / Heat-treatable steels, alloy steels and free-cutting steels - Part 17: Ball and roller bearing steels

Heat Treatments

  • End quench test austenitizing at 900 ± 5°C (Time for austenitizing as a guide: 30 min minimum);<br><br>Carburizing at 880-980°C (The carburizing temperature depends on the chemical composition of the steel, the mass of the product and the carburizing medium. If the steels are direct hardened, in general, a temperature of 950°C is not exceeded. For special procedures, for example under vacuum, higher temperatures (for example 1020-1050°C) are not unusual);<br><br>Direct and simple hardening at 820-860°C (The kind of quenching agent depends on, for example the shape of the products, the cooling conditions and the amount of furnace filling. If the steels are direct hardened and if there is a danger of distortion, they should be quenched from a temperature between the core-hardening and case-hardening temperatures);<br><br>Double hardening: Core-hardening at 860-900°C and Case-hardening at 780-820°C;<br><br>Tempering at 150-200°C (Time for tempering as a guide: 1h minimum).